The development of satisfactory adhesives for use in connection with vinyl plastics has attracted considerable attention over the years. Many common adhesives possess some desirable properties but are lacking in others. For example, the proteinaceous materials are characterized by good adhesion but are highly susceptible to water. Solutions of polyacrylates are flammable and toxic and cause swelling or solvation of the plastic.
Vinyl acetate-ethylene emulsion adhesives for use in connection with vinyl surfaces have been developed as exemplified by Knutson U.S. Pat. No. 3,734,819, Meincke U.S. Pat. No. 3,549,589 and Bissot U.S. Pat. No. 3,347,811. The emulsion adhesives, however, still exhibit inadequate bond performance for many commercial applications and particularly for use in connection with vinyl film-wood product laminates such as those formed in a continuous hot line heated reactivated laminating process.
Roeser U.S. Pat. No. 2,918,443 discloses that a combination of an N-aliphatic hydrocarbon substituted derivative of 2-pyrrolidone and a liquid aromatic hydrocarbon is an effective solvent for copolymers of vinyl chloride and vinyl acetate and that the resulting solution is useful as an adhesive.
It is the object of this invention to provide a new adhesive formulation for use in preparing vinyl film-product substrate laminates which provides a superior bond performance and to provide satisfactorily bonded vinyl film-wood product substrate laminates. These and other objects of the invention will become apparent to those skilled in the art from the following description of the invention.